PLT Scheme Science Collection

PLT Scheme Science Collection
Version 2.8

  The PLT Scheme Science Collection is a collection of modules that provide
functions for numerical computing.  The structure of the science collection and
many of the underlying algorithms were inspired by the GNU Scientific Library
(GSL).  The functions are written entirely in PLT Scheme and present a
true Scheme look-and-feel throughout.  The source code is distributed with the
science collection and licensed under the GNU Lesser General Public License

  The motivation behind the PLT Scheme Science Collection is to provide a
numerical framework for knowledge-based simulation in PLT Scheme.  Indeed,
many of the routines were originally developed as part of the PLT Scheme
Simulation Collection.  It was noted that that much of the functionality (e.g.
random number generation, random distributions, histograms and statistics) did
not depend on, or could be separated from, the underlying simulation engine.
When this was done, it was further noted that this functionality represented a
subset of the functionality in the GSL.  At that point, it was decided
to use the structure, and to the extent practical, the algorithms of the GSL as
a reference model.  Thus, the PLT Scheme Science Collection was born.

  The PLT Scheme Science Collection covers a range of topics in numerical
computing.  Functions are available for the following areas:

    * Mathematical Constants and Functions
    * Special Functions
    * Random Numbers
    * Random Distributions
    * Statistics
    * Histograms
    * Ordinary Differential Equations
    * Chebyshev Approximations

  The complete reference manual for the PLT Scheme Science Collection is available
in HTML format in the PLT Scheme Help Desk.  Or, you can contact the author at for a copy.


Version 2.8 updates the random source routines once again.  The SRFI implementation
was changed again to be compatible with the old interface.  Unchecked versions of
many functions are no provided.  These bypass the contract check are are used
internally where it is known that the contract will be met.

Version 2.7 updates the random source routines to be compatible with the new
SRFI 27 implmentation.

Version 2.6 updates the integer-in contracts to match the additional constraints
for V371.  Also added to the examples that contains most (if not
all) of the examples in one file.

Version 2.5 fixes an omission of some of the random distribution graphics
files from the subcollection.

Version 2.4

Version 2.4 is a point release of Version 2.2 where the discrete random
routines were reimplemented using Walker's O(1) algorithm.

Version 2.2

Version 2.2 of the PLT Scheme Science Collection features a reformatted
Reference Manual that is compatible with the PLT Scheme Help Desk.  The
reference manual was written in TeX abd converted to HTML using tex2page.  A
pdf version of the reference manual is also available.

Bug fixes:
The gamma-inc-Q function has been added.  It was accidentally stubbed out
in Version 2.1

Version 2.1

Version 2.1 of the PLT Scheme Science Collection added cummulative density 
functions for the rest of the 1-deminsional, continuous distributions (except
for the Gaussian tail distribution).  The corresponding graphics routines were also
updated to plot the cummulative density functions.  Also, beta, incomplete
gamma, and exponential integral special functions were implemented.

Bug fixes:
The lngamma function returned incorrect values for positive values less
than 0.5.

Downloading the science collection from PLaneT on a computer with less than
(approximately) 1 GB of memory failed.  This is caused by a bug in the PLT Scheme
setup collection that fails on large fails.  The pdf file for the reference
manual - the large file that caused the problem - was removed from the
distributed science collection.

Version 2.0

Version 2.0 of the PLT Scheme Science Collection added ordinary differential
equations.  These were needed for the PLT Scheme Simulation Collection.

Version 1.0

Initial release.